Woke up at 5 am with mine going off. 30 MPH wind out of the south blowing right down the chimney and the stove on idle as it was going to be 45 in the morning. Opened 2 windows and a door to balance the pressure inside to outside along with some burning kindling to crank the draft up.

Yes, you have to wonder when the monitor sits silent for years, whether it will come to life when needed. Glad yours did.
I wonder the same thing about all those circuit breakers in my electrical boxes, nothing to do for 50 years, will they still work if called upon?

Well that's one way to test your CO alarm. At least you know it works which beats "waking up dead." CO alarms have a manufacture date on the back. Most of them use a sensor that's reliable for 5-7 years depending on brand. I replace mine at 5 years. Cheap insurance. I also have one in the room with the boiler, one in the room adjacent to the boiler both of which are standalone type. I also have at least one on every level that are hardwired with battery backup and interconnected.

The CO monitor I bought (and the others I saw) said to not place within 15 feet of the stove, and my stove is in the middle of a 24 ft room. It also says not in the bathroom. My kitchen has gas stove, so that is out too. I put it in the bedroom. I think the problem was that it can go off from the normal minimal amounts of CO when loading coal or dumping ashes, or in the kitchen when baking, etc. The bathroom bit is probably about humidity.

Well that's one way to test your CO alarm. At least you know it works which beats "waking up dead." CO alarms have a manufacture date on the back. Most of them use a sensor that's reliable for 5-7 years depending on brand. I replace mine at 5 years. Cheap insurance. I also have one in the room with the boiler, one in the room adjacent to the boiler both of which are standalone type. I also have at least one on every level that are hardwired with battery backup and interconnected.

Well it's a kidde nighthawk. Must be 10 or 12 years old. It hasn't disabled itself. I'm still getting a new one. I was just pointing out it hadn't disabled itself.

Right. My original ones did not disable themselves, either, or flash me any beeps or codes. So I did just what you are doing, got new ones. I think the newer models are more assertive about when they want to leave us.